Play Yard

ABSTRACT

A play yard has a pair of members that are spaced apart and arranged in a longitudinal direction and has a central coupling member located in a central portion in the longitudinal direction and pivotally coupled to the pair of members. One lock mechanism operates so that one of the members is not allowed to pivot with respect to the central coupling member. Another lock mechanism operates so that the other member is not allowed to pivot with respect to the central coupling member. A lock operation mechanism simultaneously unlocks both lock mechanisms to maintain them in the unlocked state.

TECHNICAL FIELD

The present invention relates to structures for collapsing a play yard (a playpen).

BACKGROUND ART

Play yards (playpens) are well known as a product that provides a safe place where an infant or a small child can play. A play yard is a frame that defines an area where an infant or a small child can play, and typically includes a frame structure, and sewn fabric surrounding the frame structure. An example of such a play yard is described in Japanese Patent Publication No. 2008-154752 of unexamined applications. This play yard has four vertical frames (pillars), four upper horizontal frames placed in the upper parts of the vertical frames, four lower horizontal frames placed in the lower parts of the vertical frames, a bottom plate placed over the lower horizontal frames, and a frame cover placed to surround the four vertical frames, and the four side faces and the bottom face are closed. Thus, an infant in the play yard does not accidently go out of the play yard.

Typically, play yards are made light weight for portability, and are collapsed into a compact form when not in use. Of the frames of Japanese Patent Publication No. 2008-154752 of unexamined applications, each of the upper horizontal frames (horizontal members) extending in the horizontal direction is formed by pipe members extending at both ends of the horizontal frame, and a second folding portion placed in a central portion of the horizontal frame and pivotally coupled to the pipe members. In the unfolded state, the pipe member located at one of the ends, the second folding portion, and the pipe member located at the other end extend straight in alignment with each other. In the collapsed state, the pipe members pivot to form an angle of 90 degrees with respect to the second folding portion, whereby the pipe members located at both ends move toward each other so as to extend parallel to each other. Thus, each of the upper horizontal frames (the horizontal members) has pivots (pivot joints) at two positions, so that the upper horizontal frame extends straight when the play yard is in use, and is deformed into a U-shape when the play yard is collapsed.

SUMMARY OF INVENTION

However, the play yard of Japanese Patent Publication No. 2008-154752 of unexamined applications has the following problem. Since the pipe members are made pivotable with respect to the second folding portion merely via the pivots, and do not have lock means for regulating pivoting. Thus, the play yard is unstable both when the play yard is in use and when the play yard is in the collapsed state.

One possible solution to this problem is to provide both a lock mechanism, which is located on one side and which locks the pipe member located at the one end and the second folding portion so that the pipe member is not allowed to pivot with respect to the second folding portion, and a lock mechanism, which is located on the other side and which locks the pipe member located at the other end and the second folding portion so that the pipe member is not allowed to pivot with respect to the second folding portion. In this case, however, even if the pipe members and the second folding portion are released or unlocked, the release or unlock operation may not be completely performed. In this case, one of the lock mechanisms is not released or unlocked, making it difficult to perform a collapsing operation. In particular, when collapsing the play yard, a plurality of upper horizontal frames (horizontal members) need be folded, and it is therefore troublesome to reliably release or unlock all of the many lock mechanisms.

In view of the above problems, it is an object of the present invention to provide a play yard that is easy to collapse.

In order to achieve the above object, a play yard according to the present invention includes: a collapsible frame structure which includes a plurality of pillar members and a plurality of horizontal members coupling the pillar members together, and which is formed so as to surround a space accommodating an infant or a small child. At least one of the horizontal members is capable of being folded and deformed at its intermediate position, and includes a member located on one side in a longitudinal direction, a member located on the other side in the longitudinal direction, a central coupling member located in a central portion in the longitudinal direction, and pivotally coupled to the member located on the one side in the longitudinal direction and the member located on the other side in the longitudinal direction, one lock mechanism that operates so that the member located on the one side in the longitudinal direction is not allowed to pivot with respect to the central coupling member, the other lock mechanism that operates so that the member located on the other side in the longitudinal direction is not allowed to pivot with respect to the central coupling member, and a lock operation mechanism that simultaneously releases or unlocks both of the lock mechanisms to maintain the lock mechanisms in the released or unlocked state.

According to the present invention, the lock operation mechanism is included which simultaneously releases or unlocks both of the lock mechanisms to maintain the lock mechanisms in the released or unlocked state. Thus, when a parent or caregiver of the infant or the small child releases or unlocks the lock operation mechanism, both of the lock mechanisms are reliably released or unlocked, thereby facilitating a collapsing operation. Note that as used herein, the expression “capable of being folded and deformed at the intermediate position” means that the horizontal member can be folded and deformed in its intermediate portion in the longitudinal direction, which includes the central portion in the longitudinal direction and does not include both ends in the longitudinal direction.

The structure of the lock operation mechanism that maintains both lock mechanisms in each central coupling member is not particularly limited as long as the lock operation mechanism simultaneously releases or unlocks both lock mechanisms. The lock operation mechanism may either be a mechanism that is mechanically linked with both lock mechanisms, or an electric mechanism. Although the present invention is not limited to one embodiment, the one lock mechanism preferably includes one lock member which is supported by the central coupling member, and which is selectively shifted to a lock position where the member located on the one side in the longitudinal direction is not allowed to pivot, and a free position where the member located on the one side in the longitudinal direction is allowed to pivot. The other lock mechanism includes the other lock member which is supported by the central coupling member, and which is selectively shifted to a lock position where the member located on the other side in the longitudinal direction is not allowed to pivot, and a free position where the member located on the other side in the longitudinal direction is allowed to pivot. The lock operation mechanism includes a common operation element that simultaneously shifts the one lock member and the other lock member from the lock position to the free position. According to such an embodiment, the one lock mechanism and the other lock mechanism can be reliably released or unlocked when the parent or caregiver of the infant or the small child operates the single common operation element. Thus, the lock operation mechanism can be implemented in a preferable manner. Note that the operation element is not particularly limited, and may be a button or a lever.

The operation element may be in any form as long as it simultaneously releases or unlocks the one lock member and the other lock member when operated from an original position to an operation position. Operation that is performed to operate the lock members is not particularly limited. The operation element may be manually returned from the operation position to the original position. Preferably, however, the operation element is automatically returned from the operation position to the original position. For example, the operation element is operated from the original position to the operation position to shift the one lock member and the other lock member from the lock position to the free position, and the lock operation mechanism further includes a return spring that returns the operation element to the original position. According to this embodiment, since the lock operation mechanism includes the return spring, the lock members are maintained at the lock position unless the operation element is operated. Thus, the lock members are not accidentally released or unlocked.

The structure of the lock operation mechanism that moves both lock members is not particularly limited as long as it simultaneously moves both lock members. The lock operation mechanism may be a mechanism that is mechanically linked with both lock mechanisms, or an electric mechanism. As a preferable embodiment, a through hole is formed in each of the one lock member and the other lock member, a single common coupling pin extends through the through holes, a central guide portion that engage with both ends of the coupling pin is formed in the central coupling member, and the coupling pin moves along the central guide portion. According to this embodiment, since the single common coupling pin extends through the one lock member and the other lock member, the one lock member and the other lock member can be coupled together via the coupling pin to operate cooperatively. Accordingly, a structure that simultaneously releases or unlocks both lock mechanisms can be implemented as the lock operation mechanism in a preferable manner.

Behavior of these lock members when simultaneously moving both lock members is not particularly limited. These lock members may either behave differently from each other, or in the same manner. As a more preferable embodiment, the one lock member is placed on one side of the central coupling member, the other lock member is placed on the other side of the central coupling member, the one lock member and the other lock member are shaped and positioned symmetrically with respect to an imaginary central plane extending through a center of the central coupling member, and the coupling pin moves along the central plane in a direction at a right angle to a direction in which the coupling pin extends. According to this embodiment, since both lock members behave symmetrically with respect to the central plane, a structure that simultaneously releases or unlocks both lock members can be implemented in a preferable manner.

Although the present invention is not limited to an embodiment, it is preferable that the one lock member is provided with one support pin extending parallel to the coupling pin, and a tilted surface tilted with respect to a direction in which the one support pin extends, that the other lock member is provided with the other support pin extending parallel to the coupling pin, and a tilted surface tilted with respect to a direction in which the other support pin extends, that one guide portion and the other guide portion, which are symmetrically positioned on one side and the other side with respect to the central plane, and which are shaped symmetrically with respect to the central plane, are formed in the central coupling member, that the one guide portion engages with both ends of the one support pin, and guides the one support pin in a direction at a right angle to a direction in which the one support pin extends, that the other guide portion engages with both ends of the other support pin, and guides the other support pin in a direction at a right angle to a direction in which the other support pin extends, and that the operation element has a pair of legs that respectively abut on the tilted surfaces, and when the operation element is operated, the legs advance in the direction in which the support pins extend, thereby simultaneously pressing the tilted surfaces, and thus moving the one lock member and the other lock member.

According to this embodiment, since both lock members behave symmetrically with respect to the central plane, the structure that simultaneously releases or unlocks both lock members can be implemented in a preferable manner. Moreover, the legs of the operation element advance in the direction in which the support pins extend, thereby simultaneously pressing the tilted surface of the one lock member and the tilted surface of the other lock member. Accordingly, the advancing movement of the operation element in the direction in which the support pins extend can be converted to the movement of the lock members in the direction at the right angle to the direction in which the support pins extend, whereby the release or unlock operation can be reliably performed by operating the operation element.

As a preferred embodiment, the one lock member and the other lock member are respectively provided with surfaces which respectively adjoin the tilted surfaces, and which are parallel to the coupling pin, and the legs that have pressed the tilted surfaces further advance to extend parallel to and in contact with the parallel surfaces, respectively. According to this embodiment, even if the one lock member and the other lock member are subjected to any force and press the legs, the legs are not moved by the one lock member and the other lock member, and the one lock member and the other lock member can be maintained at the free position.

The pillar members need only extend at least in a vertical direction, and may be oblique members that extend so as to cross the vertical direction. The number of pillar members is not particularly limited. For example, if the space accommodating an infant or a small child is a play yard having a rectangular shape as viewed in plan, four pillar members are provided at the four corners of the rectangular space, respectively. Alternatively, if the space accommodating an infant or a small child is a play yard having a polygonal shape such as a hexagon as viewed in plan, one pillar member may be provided at each corner of the space. The horizontal members, each coupling two or more of the pillar members together, need only extend at least in a horizontal direction, and may be oblique members that extend so as to cross the horizontal direction. That is, the general shape of the frame structure as viewed in plan is not specifically limited, and may be a quadrilateral such as a rectangular or a square. Alternatively, the general shape of the frame structure as viewed in plan may be a regular polygon having an even number of corners, such as a regular hexagon or a regular octagon. Alternatively, the general shape of the frame structure as viewed in plan may be an equiangular polygon in which two opposing sides of a regular hexagon or a regular octagon are extended longer than the other sides. In other words, the frame structure is in the shape of a quadrilateral or an equiangular polygon having an even number of corners, as viewed in plan. As an embodiment, the space accommodating an infant or a small child has a quadrilateral shape as viewed in plan, the pillar members are respectively placed at corners of the quadrilateral space, and those horizontal members which are capable of being folded and deformed at their intermediate positions are arranged so as to form a pair of parallel sides of the quadrilateral space as viewed in plan.

According to this embodiment, of the horizontal members of the frame structure forming the quadrilateral space accommodating the infant or the small child such as a rectangular or square space as viewed in plan, those horizontal members which are capable of being folded and deformed at their intermediate positions are arranged so as to form a pair of sides of the quadrilateral space. Thus, in the collapsing operation, the horizontal members can be efficiently folded and deformed, and the frame structure can be reduced in size in the longitudinal direction of the horizontal members. That is, since the horizontal members are arranged parallel to each other, the shorter sides can be efficiently folded and deformed in, e.g., the quadrilateral frame structure, whereby the frame structure can be reduced in size in the direction of the shorter sides. Alternatively, the longer sides can be efficiently folded and deformed, whereby the flame structure can be reduced in size in the direction of the longer sides. Alternatively, all of the shorter sides and the longer sides can be folded and deformed, whereby the frame structure can be reduced in size in both of the directions of the shorter sides and the longer sides. Similarly, in the frame structure having a shape of a regular polygon, a pair of horizontal members arranged parallel to each other along two sides can be efficiently folded and deformed, whereby the frame structure can be reduced in size in the direction in which the two sides extend.

Note that according to the present invention, the arrangement of those horizontal members which are capable of being folded and deformed at their intermediate positions is not limited to the above arrangement, and the horizontal members may be placed in all the sides of the frame structure as viewed in plan, or may be placed in some of the sides of the frame structure as viewed in plan. In addition to this embodiment, the frame structure may have a shape of a regular polygon having an odd number of corners, such as a regular pentagon or a regular heptagon, and the horizontal members may be placed in all the sides.

ADVANTAGEOUS EFFECTS OF INVENTION

As described above, the present invention includes the one lock mechanism that operates so that the member located on the one side in the longitudinal direction is not allowed to pivot with respect to the central coupling member, the other lock mechanism that operates so that the member located on the other side in the longitudinal direction is not allowed to pivot with respect to the central coupling member, and the lock operation mechanism that simultaneously releases or unlocks both of the lock mechanisms to maintain the lock mechanisms in the released or unlocked state. Thus, both the one lock mechanism and the other lock mechanism are reliably released or unlocked when the parent or caregiver of the infant or the small child releases the lock operation mechanism. Thus, when the play yard is in use in the unfolded state, the horizontal members are locked so as not to be folded accidentally. Accordingly, when the play yard is in use, the horizontal members are not folded and deformed, allowing the frame structure to reliably serve as a framework of the play yard when the play yard is in use. In the operation of collapsing the play yard, which involves an operation of simultaneously folding and deforming the plurality of horizontal members, the other lock mechanism is also reliably released or unlocked by releasing or unlocking the one lock mechanism. This enables the parent or caregiver of the infant or the small child to easily, quickly, and reliably perform the operation of collapsing the play yard.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view showing a play yard according to an embodiment of the present invention.

FIG. 2 is a front view showing the play yard of the embodiment.

FIG. 3 is a side view showing the play yard of the embodiment.

FIG. 4 is a bottom view showing the play yard of the embodiment.

FIG. 5 is a front view schematically showing a collapsed state of the play yard of the embodiment.

FIG. 6 is a side view schematically showing the collapsed state of the play yard of the embodiment.

FIG. 7 is a bottom view schematically showing the collapsed state of the play yard of the embodiment.

FIG. 8 is a plan view showing a central portion of a horizontal member that has been locked.

FIG. 9 is a front view showing the central portion of the horizontal member that has been locked.

FIG. 10 is an illustration showing a cross section taken along line X-X in FIG. 8.

FIG. 11 is an illustration showing a cross section taken along line XI-XI in FIG. 8.

FIG. 12 is a front view showing a central coupling member.

FIG. 13 is a plan view showing the central portion of the horizontal member that has been released or unlocked.

FIG. 14 is a front view showing the central portion of the horizontal member that has been released or unlocked.

FIG. 15 is an illustration showing a cross section taken along line XV-XV in FIG. 13.

DESCRIPTION OF EMBODIMENTS

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 to 7 show an overall configuration of a play yard according to an embodiment of the present invention. FIGS. 1 to 4 show a unfolded state of the play yard when in use, and FIGS. 5 to 7 schematically show a collapsed state of the play yard. A play yard 10 includes: a frame structure 11 forming a framework of the play yard 10; a cloth-like member 12 attached to the frame structure 11 to surround the outer periphery of the frame structure 11; bar members 13 detachably attached to the frame structure 11; and a bottom board 41 supported by the bar members 13.

The play yard 10 of the present embodiment has a rectangular shape as viewed in plan. Accordingly, for convenience of description, a pair of longer side portions of the play yard 10 are herein referred to as one side of the play yard, the other side of the play yard, the left side of the play yard, the right side of the play yard, a side portion of the play yard, both side portions of the play yard, or the right and left side portions of the play yard. Moreover, a pair of shorter side portions of the play yard 10 are herein referred to as one end of the play yard, the other end of the play yard, a front end of the play yard, a rear end of the play yard, an end of the play yard, both ends of the play yard, or the front and rear ends of the play yard. The play yard 10 can not only be used as an enclosure in which an infant or a small child can plays, but also can preferably be used as a bed on which an infant or a small child can lie, as described later.

First, the frame structure 11 will be described. The frame structure 11 is formed so as to surround a space that accommodates an infant or a small child, and includes: four pillar members 14 extending in the vertical direction; a pair of horizontal members 15L, 15R provided along both side portions of the play yard; a pair of horizontal members 16, 16 provided along both ends of the play yard; and a cross pipe 17 placed so as to extend diagonally as viewed in plan. As viewed in plan, the plurality of pillar members 14 are placed in the outer periphery of the space that accommodates an infant or a small child, and each of the horizontal members 15L, 15R, 16, 16 couples adjacent ones of the pillar members 14, 14 together.

The space accommodating an infant or a small child has a rectangular shape as viewed in plan, and the pillar members 14 are placed so as to stand upright at four corners of the rectangular space. One of the horizontal members 16 is provided so as to extend between the two pillar members 14, 14 placed in one end of the play yard. The other horizontal member 16 is similarly provided so as to extend between the two pillar members 14, 14 placed in the other end of the play yard. The horizontal member 15R is provided so as to extend between the two pillar members 14, 14 placed on one side of the play yard. Specifically, the ends of the horizontal members 16, 15R are pivotally coupled to upper end blocks 14B, and when collapsing the play yard, the horizontal members 16, 15R can pivot so as to move toward the pillar members 14. Each horizontal member 16 is formed by a central coupling member 20 provided in a central portion of the horizontal member 16, a pipe 161 extending toward one side in the longitudinal direction from the central coupling member 20, and a pipe 162 extending toward the other side in the longitudinal direction from the central coupling member 20. The pipes 161, 162 are bar members having the same length.

The horizontal member 15R is formed by a central coupling member 20 provided in a central portion of the horizontal member 15R, a pipe 151 extending toward one side in the longitudinal direction from the central coupling member 20, and a pipe 152 extending toward the other side in the longitudinal direction from the central coupling member 20. The pipes 151, 152 are bar members having the same length, and are longer than the pipes 161, 162.

The pair of horizontal members 16, 16 provided in both ends of the play yard form a pair of shorter sides of the space accommodating an infant or a small child, which has a quadrilateral shape as viewed in plan. The pair of horizontal members 15L, 15R provided along both side portions of the play yard form a pair of longer sides of the space accommodating an infant or a small child.

When the play yard is in use, the central coupling member 20 locks both the pipe 161 extending toward the one side in the longitudinal direction from the central coupling member 20, and the pipe 162 extending toward the other side in the longitudinal direction from the central coupling member 20, and the horizontal member 16 is held straight as shown in FIG. 3. When the central coupling member 20 is released or unlocked, the horizontal member 16 is capable of being folded and deformed in its central portion. Thus, the horizontal member 16 is folded and deformed in its central portion when the play yard 10 is collapsed. In this state, as shown in FIG. 6 that will be described later, the pipes 161, 162 extend upward from the central coupling member 20, and the horizontal member 16 is in a V-shape. Similarly, the horizontal material 15R is also provided with the central coupling member 20, and is held straight when the play yard is in use, and is folded and deformed in its central portion when the play yard is in the collapsed state. In this state, the pipes 151, 152 extend upward from the central coupling member 20, and the horizontal member 15R is in a V-shape.

The horizontal material 15L is similarly provided with a central coupling member 20, and as shown in FIG. 2, extends straight when the play yard is in use. However, the horizontal material 15L is folded and deformed in its central portion when the play yard is in the collapsed state.

In this state, as shown in FIG. 5 that will be described later, pipes 151, 152 extend upward from the central coupling member 20, and the horizontal member 15L is in a V-shape.

Note that of the plurality of horizontal members, only the horizontal member 15L is pivotally and slidably coupled to the pillar members 14 via slide members 18 provided at two positions on the right side of the play yard. Specifically, each slide member 1 has a through hole extending in the vertical direction, and the pillar member 14 extends through the through hole, so that the pair of slide members 18 are slidable along the pillar members 14. Normally, the slide members 18 are not allowed to slide by fasteners 19, and the slide members 18 are fixed to the upper ends of the pair of pillar members 14 placed on the right side of the play yard. The slide members 18 are pivotally coupled to ends of the horizontal member 15L, respectively, and when collapsing the play yard, the horizontal member 15L can pivot so as to move toward the pillar members 14. Note that a pipe 151 located on one side in the longitudinal direction of the horizontal member 15L is made shorter than the pipe 151 located on the one side in the longitudinal direction of the horizontal member 15R by a dimension of the slide member 18. Similarly, a pipe 152 located on the other side in the longitudinal direction of the horizontal member 15L is made shorter than the pipe 152 located on the other side in the longitudinal direction of the horizontal member 15R by an amount corresponding to the dimension of the slide member 18.

When the fasteners 19 are loosened to allow the pair of slide members 18 to slide, the horizontal member 15L together with the pair of slide members 18 can move downward as shown by arrow in FIG. 2, to a position shown by two-dotted chain lines in FIG. 2. This makes it easier to place an infant or a small child into and out of the play yard 10, and allows a parent or caregiver to easily reach out a hand to the infant or the small child in the play yard 10. Note that the horizontal member 15 is herein also referred to as a front frame, because the horizontal member 15L is located at the closest position to the parent or caregiver among the four horizontal members as viewed from the parent or caregiver.

The cross pipe 17 has an X-shape, and as shown in FIG. 4, is placed so as to diagonally cross in the lower surface of the rectangular play yard 10. Specifically, the cross pipe 17 is formed by a central coupling member 23 placed in the center of the X-shape, and four pipes 171 to 174 respectively coupling the central coupling member 23 to the pillar members 14. One ends of the pipes 171 to 174 are pivotally coupled to the pillar members 14, respectively. The other ends of the pipes 171 to 174 are pivotally coupled to the central coupling member 23. In order to facilitate understanding of the drawings, FIGS. 2 and 3 show the central coupling portion 23 partially in cross section. The central coupling member 23 allows the four pipes 171 to 174 to pivot toward a position below the central coupling member 23, but restricts pivoting of the four pipes 171 to 174 to a position above the central coupling member 23. When the play yard is in use, the cross pipe 17 can be held in the unfolded state in the X-shape. As shown in FIGS. 5 to 7, when the play yard is in the collapsed state, the four pipes 171 to 174 are gathered below the central coupling member 23, and the cross pipe 17 is collapsed into a compact form.

A wheel 21 and a wheel cover 22 surrounding the outer periphery of the wheel 21 are provided at the lower end of each of the two pillar members 14, 14 placed at the other end of the play yard. The wheel 21 protrudes beyond the lower end of the wheel cover 22 and contacts a floor surface S on which the play yard is placed. Referring to FIG. 2, a portion 22 s of the wheel cover 22 which is located on the inner side of the play yard protrudes further downward than a portion of the wheel cover 22 which is located on the outer side of the play yard, and the portion 22 s contacts the floor surface S. Thus, when the play yard is used in a normal state in which all the pillar members 14 contact the floor surface S, the wheel 21 is not allowed to roll on the floor surface S.

However, when the play yard 10 is not in use, etc., one end A of the play yard 10, which is shown on the left side in FIGS. 2 and 5, is lifted, whereby the protruding portion 22 s of the wheel cover 22 is moved away from the floor surface S, and the wheel 21 contacts the floor surface S. Thus, the play yard 10 can be easily carried by tilting the play yard 10 either in the unfolded state or in the collapsed state to move the pillar members 14 at the one end of the play yard away from the floor surface S, and bringing only the wheels 21 at the lower ends of the pillar members 14 located at the other end of the play yard into contact with the floor surface S.

As described above, the horizontal members 15L, 15R, 16, 16 are capable of being folded and deformed in their respective central portions, the cross pipe 17 is capable of being folded and deformed in its central portion, and the ends of the horizontal members 15L, 15R, 16, 16 and the ends of the cross pipe 17 are pivotally coupled to the pillar members 14. Thus, the frame structure 11 can be deformed into two forms, namely the unfolded state shown in FIGS. 1 to 5 in which the play yard 10 is used, and the collapsed state shown in FIG. 6.

The cloth-like member 12 will be described below. The cloth-like member 12 is made of a material such as a net woven with spaces of about several millimeters by about several millimeters, fabric, etc., and is placed to extend over the four faces each extending between adjacent ones of the four pillar members 14. The upper end of the cloth-like member 12 hangs from the horizontal members 15L, 15R, 16, 16, and the lower end of the cloth-like member 12 is located at substantially the same height position as the cross pipe 17. This ensures that the cloth-like member 12 surrounds the bottom board 41 provided above the cross pipe 17.

The bar members 13 will be described below. The bar members 13 are a pair of bar-like bodies extending straight along both side portions of the play yard. The bar members 13 are placed in a horizontal attitude, and both ends of the bar members 13 are attached to the pillar members 14. The bar members 13 can be selectively attached to the lower ends of the pillar members 14 and the central portions of the pillar members 14, as shown by solid lines and two-dotted chain lines in FIG. 2.

That is, referring to FIGS. 2 and 3, two brackets 31, 32 are attached and fixed to each pillar member 14 at different height positions. The bracket 31 is fixed to a lower end region of each pillar member 14 at a position slightly above the cross pipe 17. The bracket 32 is fixed to the central portion of each pillar member 14. The brackets 31, 32 support the ends of the bar members 13. The hard bar members 13 are pipes having sufficient flexural strength and shear strength so that the bar members 13 can bear not only the load of an infant or a small child but also the impact load that is applied when the infant or the small child actively moves. The central regions of the bar members 13 other than both ends thereof extend along the lower surface of the bottom board 41, and both ends of the bar members 13 are attached to the brackets 31, 32. Thus, the bar members 13 stably support an infant or a small child that is placed on the upper surface of the bottom board 41. As a result, the horizontal members 15L, 15R, 16, 16 can be prevented from being folded and deformed even if the infant or the small child actively moves on the bottom board 41.

The horizontal members 15L, 15R, 16, 16 will be described in detail below. The horizontal members 15L, 15R are located along both side portions of the play yard, and each of the horizontal members 15L, 15R has the central coupling member 20 and the pipes 151, 152. The horizontal members 16, 16 are located along both ends of the play yard, and each of the horizontal members 16, 16 has the central coupling member 20 and the pipes 161, 162. Note that these horizontal members 15L, 15R, 16, 16 are different from each other only in pipe length, and are the same in the folding/deforming mechanism of the central coupling member 20. Thus, the horizontal member 16 will be described as a representative example.

FIG. 8 is a plan view showing a central portion of the horizontal member 16, and shows the central coupling member 20 in cross section. FIG. 9 is a front view showing the central portion of the horizontal member 16, and the portion on the right side of the figure is shown partially in cross section. FIG. 10 is an illustration showing a cross section taken along line X-X in FIG. 8. FIG. 11 is an illustration showing a cross section taken along line XI-XI in FIG. 8. FIGS. 8 to 11 show a state in which the horizontal member 16 is locked so that it is not allowed to pivot. FIG. 12 is a front view showing the central coupling member 20.

The horizontal member 16 includes: the pipe 161 as a member located on one side in the longitudinal direction; the pipe 162 as a member located on the other side in the longitudinal direction; the central coupling member 20 that is located in the central portion in the longitudinal direction, and pivotally couples the pipes 161, 162 together; one lock member 241 as one lock mechanism that operates so that the pipe 161 is not allowed to pivot with respect to the central coupling member 20; the other lock member 242 as the other lock mechanism that operates so that the pipe 162 is not allowed to pivot with respect to the central coupling member 20; and a button 25 as a lock operation mechanism that simultaneously releases or unlocks both lock mechanisms and maintains the lock mechanisms in the released or unlocked state.

For convenience of description, the direction in which the pipes 161, 162 extend is herein referred to as the “lateral direction” (the right-left direction), where the pipe 161 is located on the left side of the central coupling member 20, and the pipe 162 is located on the right side of the central coupling member 20. As shown in FIGS. 8 and 9, the central coupling member 20 is formed bilaterally symmetrically with respect to a centerline C passing through the center in the lateral direction, and the pipes 161, 162 are positioned bilaterally symmetrically with respect to the centerline C.

As shown in FIG. 9, one of both ends of the pipe 161, which is located closer to the center in the longitudinal direction, is pivotally coupled to one end of the central coupling member 20 via a coupling shaft 261. One of both ends of the pipe 162, which is located closer to the center in the longitudinal direction, is pivotally coupled to the other end of the central coupling member 20 via a coupling shaft 262. The central coupling member 20 has a pair of walls 201, 202 facing each other with a gap therebetween. The coupling shafts 261, 262 are placed so as to extend between the walls 201, 202. Note that the other ends of the pipes 161, 162, which are not shown in FIG. 9, are pivotally coupled to the upper end blocks 14B of the pillar members 14. The central coupling member 20 further includes an intermediate wall 203, and the intermediate wall 203 is coupled to the upper ends of the pair of walls 201, 202. As shown in the cross-sectional views of FIGS. 10 and 11, the walls 201 to 203 are placed so as to form a U-shape as viewed in cross section.

Since the pipe 161 extending in the horizontal direction contacts the wall 203 at a position closer to the end of the pipe 161 than the coupling shaft 261, downward pivoting of the pipe 161 relative to the central coupling member 20 is restricted, whereas the pipe 161 is allowed to pivot upward relative to the central coupling member 20. However, while the pipe 161 is being engaged with the one lock member 241 at a position closer to the end of the pipe 161 than the coupling shaft 261, the upward pivoting of the pipe 161 is also restricted, whereby the pipe 161 is locked so as not to be able to pivot relative to the central coupling member 20.

The pipe 162 extending in the horizontal direction also contacts the wall 203 at a position closer to the end of the pipe 162 than the coupling shaft 262, downward pivoting of the pipe 162 relative to the central coupling member 20 is restricted, whereas the pipe 162 is allowed to pivot upward relative to the central coupling member 20. However, while the pipe 162 is being engaged with the other lock member 242 at a position closer to the end of the pipe 162 than the coupling shaft 262, the upward pivoting of the pipe 162 is also restricted, whereby the pipe 162 is locked so as not to be able to pivot relative to the central coupling member 20.

As shown in FIG. 9, the central coupling member 20 protrudes downward as viewed from the coupling shafts 261, 262 extending parallel to each other, and the lock members 241, 242 are attached to positions below an imaginary plane including the coupling shafts 261, 262.

It should be noted that the coupling shafts 261, 262 extending parallel to each other are shaped and positioned bilaterally symmetrically with respect to an imaginary central plane extending through the center of the central coupling member 20. Such a central plane is represented by the centerline C in FIGS. 8, 9, and 12 and FIGS. 13 and 14 that will be described later.

A region accommodating an infant or a small child, which is surrounded by the four horizontal members 15L, 16, 15R, 16, is herein referred to as the inside of the play yard, and a region outside the region accommodating an infant or a small child is herein referred to as the outside of the play yard. The wall 202 is located in the inside of the play yard, and the wall 201 is located in the outside of the play yard.

Of the inner and outer surfaces of the wall 201, the outer surface of the wall 201 is the surface located farther away from the wall 202, and a center lock cover 30 is attached and fixed to the outer surface of the wall 201. As shown in FIG. 9, the center lock cover 30 has an elliptical shape as viewed from the front, and as shown in FIGS. 8, 10, and 11, has a three-dimensional shape that curves outward toward the center from the outer edge. A center hole 30 h is formed in the center of the center lock cover 30. The center hole 30 h extends in a direction perpendicular to the wall 201, and accommodates the button 25. When the play yard 10 is in use, the button 25 is normally located at an original position where the bottom 25 is located away from the wall 201, as shown in FIGS. 8, 10, and 11. The button 25 is provided with legs 251, 252 protruding toward the wall 202. As shown in FIG. 8, the legs 251, 252 are placed bilaterally symmetrically with respect to the centerline C passing through the center in the lateral direction, and the tip ends of the legs 251, 252 extend through a pair of through holes 20 c formed in the wall 201, respectively.

As shown in FIGS. 8 and 9, the one lock member 241 included in the one lock mechanism is located on the left side of the centerline C passing through the center in the lateral direction, the other lock member 242 included in the other lock mechanism is located on the right side of the centerline C, and the lock members 241, 242 are shaped and positioned bilaterally symmetrically with respect to the imaginary central plane extending through the center of the central coupling member 20. In order to avoid unnecessary duplication of description, the other lock mechanism 242 will be mainly described below.

As shown in FIG. 8, the other lock member 242 is placed between the pair of walls 201, 202. A through hole 244 having a circular cross section is formed along the centerline C in the center in the lateral direction. The through hole 244 is aligned with a through hole 243 that is formed similarly in the one lock member 242, and a single common coupling pin 27 extends through these through holes 243, 244.

As shown in FIG. 9, a pair of long holes 20 a are respectively formed in the walls 201, 202 along the centerline C in the center in the lateral direction. The pair of long holes 20 a have the same shape and the same dimensions and are located at the same position as viewed from the front in FIG. 9. The pair of long holes 20 a extend in the vertical direction, and respectively engage with both ends of the coupling pin 27. Thus, the coupling pin 27 can be guided by the long holes 20 a to move in the vertical direction. Note that since the long holes 20 a extend in a direction at right angles to the direction in which the coupling pin 27 extends, the coupling pin 27 moves along the centerline C in the direction at right angles to the direction in which the coupling pin 27 extends.

A central region of the other support pin 246 having a circular cross section is fixed to the lower end of the other lock member 242, which is located farthest from the centerline C. Both ends of the other support pin 246 respectively protrude toward the walls 201, 202 to engage with a pair of long holes 20 b that are respectively formed on the right side of the centerline C in the walls 201, 202 so as to extend in the lateral direction. Since the pair of long holes 20 b have the same shape and the same dimensions and are located at the same position as viewed from the front in FIG. 9, the other support pin 246 can be guided by the right long holes 20 b to move in the lateral direction. Similarly, another pair of long holes 20 b are respectively formed on the left side of the centerline C in the walls 201, 202. Like the other support pin 246, one support pin 245 is similarly fixed to the one lock member 241, and can be guided by the left long holes 20 b to move in the lateral direction.

As shown in FIG. 12, the pair of long holes 20 a are respectively formed along the centerline C in the walls 201, 202, and the two pairs of long holes 20 b are respectively formed in the walls 201, 202 so that each pair of long holes 20 b are positioned laterally symmetrically with respect to the centerline C. The pair of through holes 20 c are also formed in the wall 201 so as to be positioned bilaterally symmetrically with respect to the centerline C. Moreover, a pair of through holes 261 h and a pair of through holes 262 h are formed in the walls 201, 202, respectively. The coupling shaft 261 is inserted and fixed in the through holes 261 h, and the coupling shaft 262 is inserted and fixed in the through holes 262 h. The pair of through holes 261 h and the pair of through holes 262 h are positioned bilaterally symmetrically with respect to the centerline C.

The other lock member 242 has a tilted surface 282 at a position located away from both the other support pin 246 and the coupling pin 27.

The tilted surface 282 is located at the upper end of the other lock member 242, is tilted with respect to the direction in which the coupling pin 27 and the other support pin 246 extend, and as shown in FIG. 10, is oriented toward the wall 201. The tilted surface 282 is gently tilted upward toward the wall 202, so that a portion of the tilted surface 282 which is located closest to the wall 201 is located at the lowest position.

The tilted surface 282 is formed at a position closer to the wall 201 in the other lock member 242, and a surface 284 extending parallel to the axes of the coupling pin 27 and the other support pin 246 is formed at a position closer to the wall 202 in the other lock member 242. The parallel surface 284 and the tilted surface 282 are continuously formed in the axial direction of the coupling pin 27 and the other support pin 246.

The tilted surface 282 is located close to the tip end of the leg 252 protruding from the button 252 and extending toward the wall 202. A leg tilted surface 252 c is formed at the lower end of the tip end of the leg 252.

The leg tilted surface 252 c is formed by cutting off the tip end of the leg 252 so as to correspond to the tilted surface 282. Similarly, a tilted surface 281 and a parallel surface 283 are formed in the one lock member 241, and the tilted surface 281 is located close to a leg tilted surface 251 c formed at the tip end of the leg 251.

An engagement protrusion 292 protruding upward is formed at a position farthest from both the other support pin 246 and the coupling pin 27 in the other lock member 242. The engagement protrusion 292 is located at a position farthest from the centerline C in the upper edge of the other lock member 242, that is, at a position close to the pipe 162. As shown in FIG. 11, the tip end of the engagement protrusion 292 has an arc-shaped concave surface corresponding to the outer peripheral surface of the pipe 162. Thus, the tip end of the engagement protrusion 292 is shaped so that a portion close to the wall 201 and a portion close to the wall 202 protrude upward with respect to an intermediate portion between the walls 201, 202.

When the other lock member 242 is at a lock position, the coupling pin 27 is located at the upper end of each long hole 20 a, the other support pin 246 is located at the end closer to the centerline C in each long hole 20 b, and the engagement protrusion 292 of the other lock member 242 engages with and supports the outer peripheral surface of the pipe 162 from below. In this state, the pipe 162 is not allowed to pivot about the coupling shaft 262.

Similarly, an engagement protrusion 291 of the one lock member 241 engages with and supports the outer peripheral surface of the pipe 161 from below. In this state, the pipe 161 is not allowed to pivot about the coupling shaft 261. When the other lock member 242 is at the lock position as shown in FIG. 9, the coupling pin 27 is located at the upper end of each long hole 20 a, the other support pin 246 is located at the end closest to the centerline C in each long hole 20 b, and the leg 252 located at a position farthest from the wall portion 202. When the one lock member 241 and the other lock member 242 are located at the lock positions as shown in FIGS. 8 and 10, the button 25 as an operation element configured to simultaneously operate the two lock members 241, 242 is located at a position farthest from the wall 201. In this state, the leg tilted surface 252 c contacts a portion of the tilted surface 282 which is located closest to the wall 201.

As described above, the one lock member 241 and the other lock member 242 are supported by the central coupling member 20, and are shifted to the lock position where the pipes 161, 162 are not allowed to pivot, as shown in FIGS. 8 to 11. The one lock member 241 and the other lock member 242 are selectively shifted to a free position where the pipes 161, 162 are allowed to pivot, as shown in FIGS. 13 to 15.

FIG. 13 is a plan view showing the central portion of the horizontal member 16 that has been released or unlocked, and shows the central coupling member 20 in cross section. FIG. 14 is a front view showing the central portion of the horizontal member 16 that has been released or unlocked, and the right side of the figure is partially shown in cross section. FIG. 15 is an illustration showing a cross section taken along line XV-XV in FIG. 13.

When the button 25 is located at the original position and thus is located away from the wall 201 as shown in FIGS. 8, 10, and 11, the tip end of the leg 251 contacts a portion of the tilted surface 281 which is located closest to the wall 201, and the tip end of the leg 252 contacts the portion of the tilted surface 282 which is located closest to the wall 201.

The button 25 as a common operation element that simultaneously operates the two lock members 241, 242 is slidable in the center hole 30 h, and is movable in the direction perpendicular to the wall 201. When depressed, the button 25 advances until it contacts the wall 201, and simultaneously shifts the one lock member 241 and the other lock member 242 from the lock position to the free position via the pair of legs 251, 252.

FIGS. 13 to 15 show the lock members 241, 242 at the free position. When the one lock member 241 is located at the free position, the pipe 161 is allowed to pivot with respect to the central coupling member 20. When the other lock member 242 is located at the free position, the pipe 162 is allowed to pivot with respect to the central coupling member 20.

Specifically, when the button 25 is depressed to advance toward the wall 201, the legs 251, 252 advance in the axial direction of the pins 245, 246, 27 to simultaneously press the tilted surfaces 281, 282, respectively. Thus, the lock members 241, 242 move downward due to the pressing force. At this time, the coupling pin 27 moves downward along the long holes 20 a, and the support pins 245, 246 move in the direction away from the centerline C along the long holes 20 b. Thus, the lock members 241, 242 move to change their attitudes.

When the button 25 advances to the operation position adjacent to the wall 201, the legs 251, 252 press the tilted surfaces 281, 282 downward, respectively, and the tip ends of the legs 251, 252 reach the wall 202. Thus, the lock member 242 is shifted to the free position shown in FIGS. 13 to 15, and the lock member 241 is also shifted to the free position in an attitude bilaterally symmetrical with respect to the centerline C. In this manner, the button 25 is operated from the original position to the operation position, thereby shifting the one lock member 241 and the other lock member 242 from the lock position to the free position.

When the other lock member 242 is located at the free position, the coupling pin 27 is located at the lower end of each long hole 20 a, and the other support pin 246 is located at the end of each long hole 20 b which is located farther from the centerline C, whereby the engagement protrusion 292 is disengaged from the pipe 162 and is moved toward the centerline C. Thus, the pipe 162 is allowed to pivot about the coupling shaft 262.

Similarly, the engagement protrusion 291 of the one lock member 241 is disengaged from the pipe 161 and is moved toward the centerline C. Thus, the pipe 161 is allowed to pivot about the coupling shaft 261.

As shown in FIG. 15, when the other lock member 242 is located at the free position, the leg 252 does not contact the tilted surface 282. The leg 252 extends parallel to the parallel surface 284, and continuously contacts the parallel surface 284 from the side of the wall 201 to the side of the wall 202. Thus, even if the other lock member 242 is subjected to any force and presses the leg 252 upward, the leg 252 is not moved by the other lock member 242, and the other lock member 242 is maintained at the free position. Similarly, the leg 251 maintains the one lock member 241 at the free position. Thus, the button 25 maintains the released or unlocked state.

Note that the lock operation mechanism may further include a return spring that returns the button 25 as the operation element to the original position. The return spring is inserted between the wall 201 and the button 25, and biases the button 25 away from the wall 201.

In the present embodiment, the horizontal member 16 includes: the pipe 161 extending toward the one side in the longitudinal direction; the pipe 162 extending toward the other side in the longitudinal direction; the central coupling member 20 that is located in the central portion in the longitudinal direction, and pivotally couples the pipes 161, 162 together; the one lock member 241 as the one lock mechanism that operates so that the pipe 161 is not allowed to pivot with respect to the central coupling member 20; the other lock member 242 as the other lock mechanism that operates so that the pipe 162 is not allowed to pivot with respect to the central coupling member 20; and the button 25 as the lock operation mechanism that simultaneously releases or unlocks both lock mechanisms and maintains the lock mechanisms in the released or unlocked state. The horizontal members 15L, 15R are configured in a manner similar to the horizontal member 16.

Thus, when a parent or caregiver of an infant or a small child operates the lock operation mechanism in order to collapse the play yard 10, both the one lock mechanism and the other lock mechanism are reliably released or unlocked. As a result, a disadvantageous situation does not occur in which the one pipe 161 is allowed to pivot, while the other pipe 162 is not allowed to pivot during the operation of collapsing the play yard, whereby the collapsing operation does not become troublesome. Thus, the parent or caregiver can easily perform the operation of collapsing the play yard 10.

According to the present embodiment, the button 25 as the common operation element that simultaneously shifts the one lock member 241 and the other lock member 242 from the lock position to the free position is included as the lock operation mechanism. This enables the two lock members 241, 242 to be reliably released or unlocked by a simple button operation. Thus, the lock operation mechanism can be implemented in a preferable manner.

In the present embodiment, the one lock member 241 and the other lock member 242 are shifted from the lock position to the free position by operating the button 25 as the operation element from the original position to the operation position. According to this embodiment, the lock operation mechanism may further include the return spring that returns the button 25 to the original position. As a result, the lock members 241, 242 are located in the lock position unless the button 25 is depressed. Thus, the pipes 161, 162 are not accidentally released or unlocked.

According to the present embodiment, the through holes 243, 244 are formed in the one lock member 241 and the other lock member 242, respectively, and the single common coupling pin 27 extends through the through holes 243, 244. The long holes 20 are formed in the central coupling member 20 as central guides that engage with both ends of the coupling pin 27, respectively, and the coupling pin 27 moves along the long holes 20 a. Thus, the one lock member 241 and the other lock member 242 can be coupled together by the pin 27 to operate cooperatively. Accordingly, a structure that simultaneously releases or unlocks both lock mechanisms can be implemented as the lock operation mechanism in a preferable manner.

According to the present embodiment, the one lock member 241 is positioned on the left side of the central coupling member 20, and the other lock member 242 is positioned on the right side of the central coupling member 20. The one lock member 241 and the other lock member 242 are shaped and positioned symmetrically with respect to the imaginary central plane (the centerline C) extending through the center of the central coupling member 20, and the coupling pin 27 vertically moves along the centerline C in the direction at right angles to the direction in which the coupling pin 27 extends. Thus, both lock members 241, 242 behave symmetrically with respect to the centerline C, whereby the structure that simultaneously releases or unlocks both lock mechanisms 241, 242 can be implemented in a preferable manner.

According to the present embodiment, the one lock member 241 is provided with the one support pin 245 extending parallel to the coupling pin 27, and the tilted surface 281 tilted with respect to the direction in which the one support pin 245 extends. Similarly, the other lock member 242 is provided with the other support pin 246 extending parallel to the coupling pin 27, and the tilted surface 282 tilted with respect to the direction in which the other support pin 246 extends. The long holes 20 b are formed in the central coupling member 20 as right and left guide portions which are symmetrically located on the right and left sides with respect to the central plane (the centerline C), and which are shaped symmetrically with respect to the central plane (the centerline C). The left long holes 20 b engage with both ends of the one support pin 245 to guide the one support pin 245 in a direction at right angles to the direction in which the one support pin 245 extends. The right long holes 20 b engage with both ends of the other support pin 246 to guide the other support pin 246 in a direction at right angles to the direction in which the other support pin 246 extends. The button 25 has the pair of legs 251, 252 that abut on the tilted surfaces 281, 282, respectively. By operating the button 25, the legs 251, 252 advance in the direction in which the support pins 245, 246 extend, thereby simultaneously pressing the tilted surfaces 281, 282, and thus moving the one lock member 241 and the other lock member 242.

Since both lock members 241, 242 thus behave symmetrically with respect to the central plane (the centerline C), the structure that simultaneously releases or unlocks both lock mechanisms can be implemented in a preferable manner. Moreover, the legs 251, 252 of the button 25 advance in the direction in which the support pins 245, 246 extend, thereby simultaneously pressing the tilted surface 281 of the one lock member 241 and the tilted surface 282 of the other lock member 242. Thus, the advancing movement of the button 25 in the direction in which the support pins 245, 246 extend can be converted to the movement of the lock members 241, 242 in the direction at right angles to the direction in which the support pins 245, 246 extend, whereby the release or unlock operation can be reliably performed by the operation of the button 25.

According to the present embodiment, the one lock member 241 and the other lock member 242 are respectively provided with the surfaces 283, 284 which respectively adjoin the tilted surfaces 281, 282, and which are parallel to the coupling pin 27. The legs 251, 252 that have pressed the tilted surfaces 281, 282 further advance to extend parallel to and in contact with the parallel surfaces 283, 284, respectively. Thus, even if the lock members 241, 242 are subjected to any force and press the legs 251, 252 upward, the legs 251, 252 are not moved by the lock members 241, 242, whereby the lock members 241, 242 can be maintained in the free position.

According to the present embodiment, the space accommodating an infant or a small child has a quadrilateral shape as viewed in plan, and the pillar members 14 are respectively placed at the corners of the quadrilateral space. The horizontal members 15L, 15R, which are capable of being folded and deformed at their intermediate positions, are placed so as to form a pair of parallel sides of the quadrilateral space. Similarly, the two horizontal members 16, 16 are placed so as to form a pair of parallel sides of the quadrilateral space. Thus, in the collapsing operation, the horizontal members 15L, 15R can be efficiently folded and deformed, and the two horizontal members 16, 16 can be efficiently folded and deformed.

That is, since the horizontal members 16, 16 forming the shorter sides are placed parallel to each other in the quadrilateral frame structure 11, the shorter sides can be folded and deformed, whereby the frame structure 11 can be reduced in size in the direction of the shorter sides. Alternatively, since the horizontal members 15L, 15R forming the longer sides are placed parallel to each other, the longer sides can be folded and deformed, whereby the flame structure 11 can be reduced in size in the direction of the longer sides. Alternatively, all of the shorter sides and the longer sides can be folded and deformed, whereby the frame structure 11 can be reduced in size in both of the directions of the shorter sides and the longer sides.

Although the embodiment of the present invention is described above with reference to the drawings, the present invention is not limited to the illustrated embodiment. Various modifications and variations can be made to the illustrated embodiment without departing from the spirit or scope of the present invention.

The play yard according to the present invention is advantageously used in nursery furniture and nursery equipment. 

1. A play yard, comprising: a collapsible frame structure which includes a plurality of pillar members and a plurality of horizontal members coupling said pillar members together, and which is formed so as to surround a space accommodating an infant or a small child, wherein at least one of said horizontal members is capable of being folded and deformed at its intermediate position, and includes a member located on one side in a longitudinal direction, a member located on the other side in the longitudinal direction, a central coupling member located in a central portion in the longitudinal direction, and pivotally coupled to said member located on the one side in the longitudinal direction and said member located on the other side in the longitudinal direction, one lock mechanism that operates so that said member located on the one side in the longitudinal direction is not allowed to pivot with respect to said central coupling member, the other lock mechanism that operates so that said member located on the other side in the longitudinal direction is not allowed to pivot with respect to said central coupling member, and a lock operation mechanism that simultaneously releases or unlocks both of said lock mechanisms to maintain said lock mechanisms in the released or unlocked state.
 2. The play yard according to claim 1, wherein said one lock mechanism includes one lock member which is supported by said central coupling member, and which is selectively shifted to a lock position where said member located on the one side in the longitudinal direction is not allowed to pivot, and a free position where said member located on the one side in the longitudinal direction is allowed to pivot, said other lock mechanism includes the other lock member which is supported by said central coupling member, and which is selectively shifted to a lock position where said member located on the other side in the longitudinal direction is not allowed to pivot, and a free position where said member located on the other side in the longitudinal direction is allowed to pivot, and said lock operation mechanism includes a common operation element that simultaneously shifts said one lock member and said other lock member from said lock position to said free position.
 3. The play yard according to claim 2, wherein said operation element is operated from an original position to an operation position to shift said one lock member and said other lock member from said lock position to said free position, and said lock operation mechanism further includes a return spring that returns said operation element to said original position.
 4. The play yard according to claim 2, wherein a through hole is formed in each of said one lock member and said other lock member, and a single common coupling pin extends through said through holes, a central guide portion that engage with both ends of said coupling pin is formed in said central coupling member, and said coupling pin moves along said central guide portion.
 5. The play yard according to claim 4, wherein said one lock member is placed on one side of said central coupling member, said other lock member is placed on the other side of said central coupling member, and said one lock member and said other lock member are shaped and positioned symmetrically with respect to an imaginary central plane extending through a center of said central coupling member, and said coupling pin moves along said central plane in a direction at a right angle to a direction in which said coupling pin extends.
 6. The play yard according to claim 5, wherein said one lock member is provided with one support pin extending parallel to said coupling pin, and a tilted surface tilted with respect to a direction in which said one support pin extends, said other lock member is provided with the other support pin extending parallel to said coupling pin, and a tilted surface tilted with respect to a direction in which said other support pin extends, one guide portion and the other guide portion, which are symmetrically positioned on one side and the other side with respect to said central plane, and which are shaped symmetrically with respect to said central plane, are formed in said central coupling member, said one guide portion engages with both ends of said one support pin, and guides said one support pin in a direction at a right angle to a direction in which said one support pin extends, said other guide portion engages with both ends of said other support pin, and guides said other support pin in a direction at a right angle to a direction in which said other support pin extends, and said operation element has a pair of legs that respectively abut on said tilted surfaces, and when said operation element is operated, said legs advance in said direction in which said support pins extend, thereby simultaneously pressing said tilted surfaces, and thus moving said one lock member and said other lock member.
 7. The play yard according to claim 6, wherein said one lock member and said other lock member are respectively provided with surfaces which respectively adjoin said tilted surfaces, and which are parallel to said coupling pin, and said legs that have pressed said tilted surfaces further advance to extend parallel to and in contact with said parallel surfaces, respectively.
 8. The play yard according to claim 1, wherein said space accommodating the infant or the small child has a quadrilateral shape as viewed in plan, said pillar members are respectively placed at corners of said quadrilateral space, and those horizontal members which are capable of being folded and deformed at their intermediate positions are arranged so as to form a pair of parallel sides of said quadrilateral space. 